1. Technical Field of the Invention
The present invention relates to a combustion gas bleeding probe and a method for running the probe, and more particularly to a combustion gas bleeding probe and a method for running the probe used for, for instance, a cement kiln chlorine bypass facility that bleeds a kiln exhaust gas passage running from an end of the cement kiln to a bottom cyclone, of a part of combustion gas to remove chlorine.
2. Description of the Related Art
It is noticed that chlorine, sulfur, alkali and the like cause troubles such as preheater clogging in cement manufacturing facility, and especially chlorine exerts the most harmful effect, so that a cement kiln chlorine bypass system that bleeds a section near an inlet hood of a part of combustion gas to remove chlorine is used. And, the quantity of chlorine carried into a cement kiln increases with the increase in the amount of practical use of chlorine-content recycled resources in recent years, so that augmenting capability of the chlorine bypass facility becomes inescapable.
In the chlorine bypass facility, in order to extract a part of combustion gas from a section near an entrance hood, a probe is mounted so as to protrude near the entrance hood and an extracted gas disposal equipment is installed in a rear stage of this probe. Since a head of the probe is exposed to a high temperature circumstance at approximately 1000□ near the entrance hood, steel casting with a high degree of heat resistance needs to be used for the head, or it is necessary to cool the head with a cooling air taken in from the outer side of the entrance hood to protect the probe.
Further, since volatile components such as chlorine in a kiln exhaust gas are condensed to a fine powder portion of bypass dust by carrying out rapid cooling to approximately 450° or less with the probe, a classification means such as a cyclone is arranged to a gas extraction and discharge equipment in the rear stage, and bypass dust is classified into coarse powder dust with low volatile component concentration and fine powder dust with high volatile component concentration, and the coarse powder dust is returned to a kiln system, and only fine powder dust is discharged out of the system through the chlorine bypass facility to reduce the quantity of the bypass dust. Therefore, it is required to carry out rapid cooling of the kiln exhaust gas in the probe from this point also.
From the above-mentioned point of view, in Patent document 1 is described a combustion gas bleeding probe comprising: an inner tube in which a hot gas flows; an outer tube surrounding the inner tube; cold gas discharge ports drilled in the inner tube; and a cold gas feeding means for feeing a cold gas between the inner tube and the outer tube and for discharging cold gases from the discharge ports in directions substantially perpendicularly of a suction direction of a hot combustion gas and toward the center of the combustion gas.
Patent document 1: International Patent Publication WO2005/050114 Pamphlet
However, although in case that a cross flow cooling type probe with high chlorine removing capability such as the combustion gas bleeding probe described in Patent document 1 is used, in accordance with a condition where the probe is installed, such as an angle of the probe installed, a combustion gas to be sucked and dust contained in the combustion gas unevenly flow in the probe or a secondary mixing cooler, which induces abrasion of the probe and uneven gas temperature distribution in the probe, causing short lifetime and deteriorated performance of the probe.
In addition, in order to prevent the abrasion of the probe and the uneven distribution of the gas temperature in the probe, abrasion prevention plates or uneven flow prevention plates were installed, but effects as expected could not been obtained.
The present invention has been made in consideration of the above-mentioned problems in conventional arts and the object thereof is to elongate lifetime of the combustion gas bleeding probe and improve performance such as chlorine removing ability thereof.